If You've Ever Felt the Sudden Urge to Poop When You Walk Into a Bookstore, Science Has an Explanation for That

Have you ever been casually browsing the shelves of your local bookshop and suddenly felt the need to go No. 2? If so, you’re not alone.

Feeling the urge to poop while visiting a bookstore is a real thing that’s referred to as the Mariko Aoki phenomenon. In a recent Instagram reel , gastroenterologist Dr. Will Bulsiewicz, MD, known as The Gut Health MD and author of Fiber Fueled , brought up the subject.

It’s a “legitimate question,” he says in the post. And there are several reasons why it might happen.

“Bookstores tend to be quiet, relaxing places, which allow your body to relax, which allows your bowels to relax,” explains Dr. Aditi Stanton, MD , a board-certified gastroenterologist at Gastro Health in Cincinnati, Ohio.

Being in such a relaxing space can activate your parasympathetic nervous system, which is responsible for bodily functions that you don’t typically think about, like digestion and heartbeats, says Dr. Supriya Rao, MD , a board-certified physician in internal medicine, gastroenterology, obesity medicine and lifestyle medicine.

So why exactly does this happen? Gastroenterologists explain what’s behind feeling like you need to poop while in a bookstore.

What Is the Mariko Aoki Phenomenon?

This idea that bookshops might trigger a bowel movement for some people has been around for decades but it was first written about in the mid-1980s. Then, a woman named Mariko Aoki wrote to a Japanese magazine describing her need to use the bathroom after browsing a bookstore, according to a 2022 McGill University article .

The magazine received several reports from readers who’ve experienced the same thing and published an article on the subject in its next issue.

While there hasn’t been any scientific research on the topic, Dr. Stanton says, “The phenomenon is interesting and has many theories behind it.”

What Is the Parasympathetic Nervous System—and How Does It Relate to Digestion?

The parasympathetic nervous system is part of your autonomic nervous system, and it’s responsible for several functions that happen automatically, like blood pressure, sweating and digestion, according to the Cleveland Clinic . It’s the opposite of your sympathetic nervous system, which controls your “fight or flight” response.

“We often think of the sympathetic nervous system as ‘fight or flight’ and the parasympathetic system as ‘rest and digest,’” Dr. Stanton says.

Related: Wait, Is It Normal to Poop 5 Times a Day?

She explains that the parasympathetic nervous system includes the vagus nerve, which carries signals throughout the neck, chest and abdomen, and supplies nerves into the intestine.

“When the parasympathetic nervous system is activated, digestion is stimulated, adrenaline is inhibited and the rectum is relaxed, allowing defecation to occur,” Dr. Stanton says.

This relaxed state also explains why you often get sleepy after eating a big meal—Dr. Rao says, “Your body is trying to conserve energy, slowing your heart rate down and increasing intestinal activity that promotes digestion.”

Can Visiting Bookstores Really Help You Poop?

When the parasympathetic nervous system gears up and you’re in a relaxed state, the sphincter, the muscles around the anus, relaxes, and you may be ready to poop, says Dr. David Kahana, MD , a gastroenterologist and medical nutritionist.

“If you haven't evacuated and you find yourself in a relaxed environment, it would be very normal for you to move your bowel,” he explains.

Other factors could also be contributing to your urge to go no. 2, Dr. Kahana says.

Related: This Bathroom Issue Is One of the Most Common Signs of Colon Cancer, According to a GI Doc

In his post, Dr. Bulsiewicz suggested that bookstores could have an autonomous sensory meridian response (ASMR) effect, where someone gets a tingling sensation when they encounter certain audiovisual stimuli. Research suggests that these stimuli can activate certain areas of the brain, improve mood and promote a sense of calm.

Many bookstores have coffee shops, so it could be the scent of the coffee or the paper and ink of the books, Dr. Kahana adds, or the sound of pages of books being turned.

Coffee has also been shown to stimulate the digestive system and trigger bowel movements, Dr. Stanton says. “There may be some components of this phenomenon that are driven by the smell of paper and the vast number of books around you may be what is so relaxing for people that it causes this urge to have a bowel movement,” Dr. Stanton says.

Another theory is related to Pavlov’s dog experiments. If you tend to read while you’re in the bathroom, the association of being around books may make you feel the need to poop, according to Dr. Kahana.

Related: If Your Poop Looks Like This, It's Time to See a Doctor

Dr. Stanton notes that when this phenomenon was first described in the mid-1980s, smartphones didn’t exist so more people may have taken paper reading materials into the toilet with them, “carrying with them the smell of paper or old books.”

Is It Just Bookstores?

Bookstores have a calming effect on many people, which is likely why they describe needing to poop when they’re there. But Dr. Rao says the same thing could probably happen in any space that you find relaxing.

For example, in a 2023 Instagram post , gastroenterologist Joseph Salhab described how shopping at certain stores might make you feel the urge to poop. Some people commented that they experienced this while shopping at retailers like T.J. Maxx or Lowe’s.

Anywhere—a bookstore, shop or cafe—could help you relax, activate the parasympathetic nervous system and get your bowels moving, Dr. Stanton explains.

“Some people have mental associations with particular locations and needing to use the bathroom,” Dr. Rao says. “It’s an interesting phenomenon.”

Next, read about what your poop can reveal about your health .

Sources:

• Aditi Stanton, MD, board-certified gastroenterologist at Gastro Health in Cincinnati, Ohio
• Supriya Rao , MD, board-certified physician in internal medicine, gastroenterology, obesity medicine and lifestyle medicine
• David Kahana , MD, a gastroenterologist and medical nutritionist
• The Unbearable Poopness of Bookstores , McGill University
• Parasympathetic Nervous System , Cleveland Clinic
• Brain function effects of autonomous sensory meridian response (ASMR) video viewing , Frontiers in Neuroscience